lifepan of a 4.0?

I cannot speak from experience my 4.0 only has 127,000 miles, but others have said mine is just broken in and over 200,000 is common WITH PROPER MAINTENANCE.

If that rig has the AX-15 that will go before the engine

139,382 miles here, all but the first 50,000 under a blower. So as ufatbastehd says, "with proper maintenance."

The timing chain is the only bit that needs checking some where around 200,000 miles.

I just sold my '93 that had over 255,000 miles on it and was still running like a champ!

Mark

The 4.0 in my YJ is at 220K km and the 4.0 in my ZJ it is at 291K km.

Crank Position Sensor can stop on cold suddenly when it goes bad with age.

----------------- TheSnoMan.com

Yes, proper maintainance is key here

People that have trouble with AX15's generally either beat them or never change the lube in them. You "should" change the lube in it every 30 or 40K if max life is your goal.

----------------- TheSnoMan.com

rilly. :) no kiddin.

Mine gave me a warning by cutting out every time I slowed to a stop.

Mine had 300,000 miles on it before one of the rod bearings started knocking, it still ran fine, didn't smoke, and the timing chain was a bit loose but nowhere close to failing.

GREAT engine!

Jeff DeWitt

you were lucky, at east you had some warning..

----------------- TheSnoMan.com

No warning when my CPS went. 2000 XJ 4.0 137K. Curious, are there any other "mission critical" parts that should be kept in the rig in case of failure?

Steve

Murphy's Law applies, as always, any part you have with you will NOT be the part you will need. :-(

Pretty much so.... I would replace CPS before it fails if it has ove

100K on it. They are not that expensive and are known to fail with age. It is kinda a crap shoot for guessing what else is likley to fail with dire results after CPS.

----------------- TheSnoMan.com

I keep a cell phone.

What you stash in the rig all depends on how far and how difficult your trip is going to be.

Replacing the CPS sensor on the trail must rank up high in the pain-in-the-ass scale.

Sitting in the back of my ZJ right now is

- tire puncture repair kit

- compressor (little bitty one)

- 50/50 cooling fluid & water (I mix my own it's cheaper)

- brake fluid (probably need to take that out as I found the leak)

- oil (for topping it off)

- hose repair kit (clamps, splices)

- spare belt (I have to keep one because my ZJ uses a non standard size 108") Got to feed the blower.

- distributor cap/rotor/spare wire/plug (I have had a plug crack in my old truck)

cue beginning of stuff-I-have-in-the-jeep thread. :)

So true. I had a fanbelt break on a Porsche at 30K. Bought two as a replacement. The darn thing outlasted the engine at about 250K miles.

I carry about the same plus u-joints (one of each type on your vehicle), bailing wire and electical wire.

I don=B4t carry this but for extreme trips very far from help maybe even fuel pump, PCM, starter and alternator in addition to the CPS sensor.